To find the number of grams of hydrochloric acid required to react completely with 4.30g of zinc, we can follow these steps:
1. Write the balanced chemical equation:
Zn + 2HCl → ZnCl2 + H2
2. Convert grams of zinc to moles:
Moles = grams/atomic mass Zn
Moles = 4.30g/65.4g/mol = 0.0658 mol Zn
3. Use the balanced equation to convert moles of Zn to moles of HCl:
From the equation, we see that 1 mole of Zn reacts with 2 moles of HCl.
Moles of HCl = 0.0658 mol Zn * (2 mol HCl/1 mol Zn) = 0.1316 mol HCl
4. Convert moles of HCl to grams of HCl:
Grams HCl = Moles HCl * Molar mass HCl
Molar mass of HCl:
Atomic mass of H = 1g/mol
Atomic mass of Cl = 35.4g/mol
Molar mass HCl = 1g/mol + 35.4g/mol = 36.4g/mol
Grams HCl = 0.1316 mol HCl * 36.4g/mol = 4.79g HCl
Therefore, 4.79 grams of hydrochloric acid are required to react completely with 4.30g of zinc.
To calculate the number of molecules of gas produced, we continue with these steps:
5. Use the balanced equation to find the ratio of moles of H2 gas to moles of Zn:
From the balanced equation, we see that 1 mole of Zn produces 1 mole of H2 gas.
6. Calculate the moles of H2 gas:
Moles of H2 = 0.0658 mol Zn
7. Convert moles of H2 gas to molecules of H2 gas:
One mole of any gas contains Avogadro's number of molecules, which is approximately 6.022 x 10^23.
Molecules of H2 = Moles of H2 * Avogadro's number
Molecules of H2 = 0.0658 mol H2 * 6.022 x 10^23 molecules/mol = 3.96 x 10^22 molecules
Therefore, approximately 3.96 x 10^22 molecules of H2 gas will be produced.